Usage share of web browsers

The usage share of web browsers is the proportion, often expressed as a percentage, of visitors to a group of web sites that use a particular web browser. Web browser usage share varies from region to region as well as through time.

Not all requests are generated by a user, as a user agent can make requests at regular time intervals without user input. In this case, the user's activity might be overestimated. Some examples:

Certain anti-virus products fake their user-agent to appear to be popular browsers. This is done to trick attack sites that might display clean content to the scanner, but not to the browser. The Register reported in June 2008 that traffic from AVG Linkscanner, using an IE6 user-agent, outstripped human link clicks by nearly 10 to 1.[1]

A user who revisits a site shortly after changing or upgrading browsers may be double-counted under some methods; overall numbers at the time of a new version's release may be skewed.[2]

Occasionally websites are written in such a way that they effectively block certain browsers. One common reason for this is that the website has been tested to work with only a limited number of browsers, and so the site owners enforce that only tested browsers are allowed to view the content, while all other browsers are sent a "failure" message, and instruction to use another browser.[3] Many of the untested browsers may still be otherwise capable of rendering the content. Sophisticated users who are aware of this may then "spoof" the user-agent in order to gain access to the site.

The browsers Chrome, Safari and Opera will under some circumstances fetch resources before they need to render them, so that the resources can be used faster if they are needed. This technique, prerendering or pre-loading, may inflate the statistics for the browsers using it because of pre-loading of resources which are not used in the end.[4]

It is also possible to underestimate the usage share by using the number of requests, for example:

Opera and Gecko-based browsers since Firefox 1.5 use fast Document Object Model (DOM) caching. JavaScript is only executed on pageload from net or disk cache, but not if it is loaded from DOM cache. This can have an impact on JavaScript-based tracking of browser statistics.[5]

While most browsers generate additional page hits by refreshing web pages when the user navigates back through page history, some browsers (such as Opera) reuse cached content without resending requests to the server.[6][7]

Generally, the more faithfully a browser implements HTTP's cache specifications, the more it will be under-reported relative to browsers that implement those specifications poorly.[7]

Browser users may run site, cookie and JavaScript blockers which cause those users to be under-counted. For example, common AdBlock blocklists such as EasyBlock include sites such as StatCounter in their privacy lists, and NoScript blocks all JavaScript by default. addons.mozilla.org reports 15.0 million users of AdBlock variants and 2.2 million users of NoScript.

Users behind a caching proxy (e.g. Squid) may have repeat requests for certain pages served to the browser from the cache, rather than retrieving it again from the Internet.

Web sites often include code to detect browser version to adjust the page design sent according to the user agent string received. This may mean that less-popular browsers are not sent complex content (even though they might be able to deal with it correctly) or, in extreme cases, refused all content.[8] Thus, various browsers have a feature to cloak or spoof their identification to force certain server-side content.

Many Android browsers identify themselves as Safari on iOS (among other things) in order to aid compatibility.[9][10]

Many Linux browsers identify themselves as Safari on Mac OS X (among other things) in order to aid compatibility.[11]

Net Applications and W3Counter[citation needed] use unique visitors to measure web usage.[12] This has the effect that users visiting a site ten times will only be counted once by these sources, while they are counted ten times by statistics companies that measure page hits.

To supplement statistics from their unique visitors measurements Net Applications uses country-level weighting.[13] The goal of weighting countries based on their usage is to combat selection area based sampling bias caused by discrepancies in the percentage of tracked hits in the sample and the percentage of global usage documented by third party sources caused by the heavier levels of market usage.[14]

StatCounter reports desktop (including laptop) and mobile browser share separately. For consistency, each desktop browser share has been reduced by multiplying it by the current overall desktop share versus mobile. Similarly, mobile browser shares have each been multiplied by the overall mobile percentage. This avoids having greater than 100% usage share when combining mobile and desktop.

^StatCounter reports desktop and mobile browser share separately; we report them together. For consistency, each desktop browser share has been reduced by multiplying it by the current overall desktop share versus mobile. Similarly, mobile browser shares have each been multiplied by the overall mobile percentage.

This site counts the last 15,000 page views from each of approximately 70,000 websites. This limits the influence of sites with more than 15,000 monthly visitors on the usage statistics. W3Counter is not affiliated with the World Wide Web Consortium (W3C).

Net Applications bases its usage share on statistics from 40,000 websites having around 160 million unique visitors per month. The mean site has 1300 unique visitors per day.

On 1 August 2009, Net Applications began weighting its raw data based on the number of internet users in the countries concerned, using data from the CIA ; the changes were applied retroactively to older data, starting with November 2007.[17] Quarterly data prior to Q1 2008, is reported with a different methodology compared to quarterly data starting with Q1 2008, so combining these data sets and/or using them as the basis for identifying historical trends could result in flawed information.

* Net Applications no longer reports data prior to November 2007 because of this change in methodology.

Note†: Wikimedia has recently had a large percentage of unrecognised browsers, previously counted as Firefox, that are now assumed to be Internet Explorer 11 fixed ONLY for February 2014 numbers. And February 2014 numbers include mobile for Internet Explorer and Firefox (not included in Android). Chrome does not include mobile numbers (Android does).

TheCounter.com identifies sixteen versions of six browsers (Internet Explorer, Firefox, Safari, Opera, Netscape, and Konqueror). Other browsers are categorised as either "Netscape compatible" (including Google Chrome, which may also be categorized as "Safari" because of its "Webkit" subtag) or "unknown". Internet Explorer 8 is identified as Internet Explorer 7. Monthly data includes all hits from 2008-02-01 until the end of the month concerned. More than the exact browser type, this data identifies the underlying rendering engine used by various browsers, and the table below aggregates them in the same column.

Market share for several browsers between 1995 and 2010, illustrating the First Browser War (NN vs IE). Firefox was originally named "Phoenix", a name which implied that it would rise like a Phoenix after Netscape was killed off by Microsoft.